Migration and health study: a socio-ecological analysis of sexual health among migrants in Manitoba, Canada

BACKGROUND

To develop effective public health policies, programs, and services tailored to the unique sexual health needs of migrant populations, it is essential to understand the myriad socio-ecological factors that influence their sexual health. This qualitative community-based participatory study aimed to explore factors influencing migrants' sexual health at different socio-ecological levels in a Canadian setting.

METHODS

Participants (n = 34) from African, Caribbean, Black; Latin American; South Asian; Middle Eastern, as well as East and Southeast Asian communities were recruited across Manitoba using printed flyers, community organizations, and social media. Individual interviews, conducted in English, French, Mandarin, Cantonese, Tagalog, Arabic, Swahili, and Tigrinya languages, explored questions relating to sexual health and experiences with service providers. Data were analyzed using reflexive thematic analysis and socio-ecological systems theory.

RESULTS

The study uncovered a range of individual, interpersonal, institutional, and socio-structural factors that affect the sexual health of migrants in Manitoba. Individual factors such as sexual health knowledge and testing practices, interpersonal factors like the type of sexual partnerships, institutional factors such as sexual health information needs, language, and service access barriers, and structural-level factors like gender norms and HIV stigma exerted a significant influence on the sexual health practices of study respondents. Sexual health awareness was influenced by various factors including length of time in Canada and involvement in community-based services. Study respondents identified issues related to access to HIV testing and sexual health information, as well as language barriers, racism in healthcare, and HIV stigma. Gender and social norms played a significant role in discouraging communication about sex and safer sex practices.

CONCLUSIONS

The study highlights the complex interplay of factors that influence the sexual health of migrants, and the need for targeted sexual health awareness campaigns and provision of sexual health information in languages spoken by migrants. Public health interventions focused on improving the sexual health outcomes for migrants should consider the socio-ecological elements identified in this study. These findings can inform public health campaigns to increase access to services and address sexual health inequities among migrant communities in Canada.

The Medicine Wheel: informing the management of tuberculosis outbreaks in Indigenous communities

Many Indigenous communities in Canada experience endemic tuberculosis with superimposed periodic epidemic outbreaks. Failures in outbreak management have resulted in the "seeding" of future infection and disease. In this paper we present a model that may be used in planning, implementation and review of tuberculosis outbreak management in Cree Indigenous communities in Canada, based on the Medicine Wheel, a paradigm for holistic living. In the context of tuberculosis management, the Medicine Wheel provides a path for the establishment of respectful cross-cultural relationships, the expression of values through action, true community engagement and partnership, and the establishment of culture-based processes of transparency, accountability and change.

"Because of COVID…": The impacts of COVID-19 on First Nation people accessing the HIV cascade of care in Manitoba, Canada

BACKGROUND

The COVID-19 pandemic (March 2020-May 2023) had a profound effect around the world with vulnerable people being particularly affected, including worsening existing health inequalities. This article explores the impact of the pandemic on health services for First Nations people living with HIV (FN-PWLE) in Manitoba, Canada. This study investigated perceptions of both health care providers and FN-PWLE through qualitative interviews occurring between July 2020 and February 2022 to understand their experience and identify lessons learned that could be translated into health system changes.

METHODS

Using a qualitative, participatory-action, intentional decolonizing approach for this study we included an Indigenous knowledge keeper and Indigenous research associates with lived experience as part of the study team. A total of twenty-five [25] in-depth semi-structured interviews were conducted with eleven healthcare providers (HCPs) and fourteen First Nation people with lived HIV experience (FN-PWLE). In total, 18/25 or 72% of the study participants self-identified as First Nation people.

RESULTS

The COVID-19 pandemic negatively impacted health services access for FN-PWLE, a) disrupted relationships between FN-PWLE and healthcare providers, b) disrupted access to testing, in-person appointments, and medications, and c) intersectional stigma was compounded. Though, the COVID-19 pandemic also led to positive effects, including the creation of innovative solutions for the health system overall.

CONCLUSIONS

The COVID-19 pandemic exaggerated pre-existing barriers and facilitators for Manitoba FN-PWLE accessing and using the healthcare system. COVID-19 impacted health system facilitators such as relationships and supports, particularly for First Nation people who are structurally disadvantaged and needing more wrap-around care to address social determinants of health. Innovations during times of crisis, included novel ways to improve access to care and medications, illustrated how the health system can quickly provide solutions to long-standing barriers, especially for geographical barriers. Lessons learned from the COVID-19 pandemic should be considered for improvements to the health system's HIV cascade of care for FN-PWLE and other health system improvements for First Nations people with other chronic diseases and conditions. Finally, this study illustrates the value of qualitative and First Nation decolonizing research methods. Further studies are needed, working together with First Nations organizations and communities, to apply these recommendations and innovations to change health care and people's lives.

Social and structural barriers and facilitators to HIV healthcare and harm reduction services for people experiencing syndemics in Manitoba: study protocol

INTRODUCTION

In Manitoba, Canada, there has been an increase in the number of people newly diagnosed with HIV and those not returning for regular HIV care. The COVID-19 pandemic resulted in increased sex and gender disparities in disease risk and mortalities, decreased harm reduction services and reduced access to healthcare. These health crises intersect with increased drug use and drug poisoning deaths, houselessness and other structural and social factors most acutely among historically underserved groups. We aim to explore the social and structural barriers and facilitators to HIV care and harm reduction services experienced by people living with HIV (PLHIV) in Manitoba.

METHODS AND ANALYSIS

Our study draws on participatory action research design. Guiding the methodological design are the lived experiences of PLHIV. In-depth semi-structured face-to-face interviews and quantitative questionnaires will be conducted with two groups: (1) persons aged ≥18 years living or newly diagnosed with HIV and (2) service providers who work with PLHIV. Data collection will include sex, gender, sociodemographic information, income and housing, experiences with the criminal justice system, sexual practices, substance use practices and harm reduction access, experiences with violence and support, HIV care journey (since diagnosis until present), childhood trauma and a decision-making questionnaire. Data will be analysed intersectionally, employing grounded theory for thematic analysis, sex-based and gender-based analysis and social determinants of health and syndemic framework to understand the experiences of PLHIV in Manitoba.

ETHICS AND DISSEMINATION

We received approval from the University of Manitoba Health Ethics Research Board (HS25572; H2022:218), First Nations Health and Social Secretariat of Manitoba, Nine Circles Community Health Centre, Shared Health Manitoba (SH2022:194) and 7th Street Health Access Centre. Findings will be disseminated using community-focused knowledge translation strategies identified by participants, peers, community members and organisations, and reported in conferences, peer-reviewed journals and a website (www.alltogether4ideas.org).

Impact of the COVID-19 pandemic on access to HIV testing and condom use among two-spirit, gay, bisexual, and queer (2SGBQ+) men in Manitoba

This cross-sectional online survey (n = 347) examined the impact of the COVID-19 pandemic on access to HIV testing and condom use among Two-Spirit, gay, bisexual, and queer (2SGBQ+) men in Manitoba. Logistic regression assessed the relationship between socio-demographics and the impact of COVID-19 on access to HIV testing and condom use. Among those who answered a question on testing (n = 282), 27.7% reported reduced access to HIV testing. Among those who answered questions on condom use (n = 327), 54.4% reported decreased use of condoms. Compared to living in Winnipeg, living in a medium-sized city (Brandon) and in rural and remote areas were both associated with higher odds of reporting reduced access to HIV testing due to COVID-19. Participants who were dating (vs. married or partnered) were significantly more likely to report reduced access to HIV testing, but less likely to report decreased use of condoms, while younger age was associated with decreased use of condoms. Service providers must be prepared to respond to the impact of COVID-19 on HIV testing and condom use among younger, sexually active 2SGBQ + men, as well as those who live in small, rural, and remote areas in Manitoba.

Relationship between sociodemographics, loss of income, and mental health among two-spirit, gay, bisexual, and queer men in Manitoba during the COVID-19 pandemic

This study examined the relationship between loss of income due to the COVID-19 pandemic and worsening mental health among a sample of 366 Two-Spirit, gay, bisexual, queer (2SGBQ+) men in Manitoba. Data were drawn from a cross-sectional online survey among 2SGBQ+ men in Manitoba. Logistic regression assessed the relationship between sociodemographics, loss of income due to COVID-19 (independent variable) and worsening of mental health (analytic outcome). Among all respondents in the sample (N = 366), 55% indicated worsening of their mental health. In logistic regression, compared to participants who did not experience any loss of income, those who experienced loss of income due to the COVID-19 pandemic were significantly more likely to report worsening mental health (Adjusted Odds Ratio [AOR] = 8.32, 95% Confidence Interval[CI] = 3.54-19.54). Compared to participants who self-identified as gay, bisexual-identifying participants were less likely to report worsening mental health (AOR = .35, 95%CI = 0.13-0.96). Finally, as compared to participants who were married or partnered, participants who were dating (AOR = 3.14, 95%CI = 1.60-6.17), single (AOR = 4.08, 95%CI = 1.75-9.52), and separated/divorced/widowed (AOR = 15.08, 95%CI = 2.22-102.51) were all significantly more likely to report experiencing a worsening of mental health due to the COVID-19 pandemic. This study highlights the need to develop robust public strategies for sub-populations of 2SGBQ+ men (non-gay identified sexual minorities and 2SGBQ+ men who may be more socially isolated). Specific targeted and tailored public health interventions designed with the unique needs of 2SGBQ+ men in Manitoba may be required to increase their access to socio-economic and mental health supports.

Paying the price? Academic work and parenting during COVID-19

INTRODUCTION

The shift to remote working/learning to slow transmission of the SARS-CoV-2 virus has had widespread mental health impacts. We aimed to describe how the COVID-19 pandemic impacted the mental health of students and faculty within a health sciences faculty at a central Canadian university.

METHODS

Via an online survey, we queried mental health in the first four months of the COVID-19 pandemic quantitatively (scale: 1 (most negative)-100 (most positive)) and qualitatively.

RESULTS

The sample (n = 110) was predominantly women (faculty 39/59; [66.1%]; students 46/50; [92.0%]). Most faculty were married/common law (50/60; [84.8%]) and had children at home (36/60; [60.0%]); the opposite was true for most students.Faculty and students self-reported comparable mental health (40.47±24.26 and 37.62±26.13; respectively). Amongst women, those with vs. without children at home, reported significantly worse mental health impacts (31.78±23.68 vs. 44.29±27.98; respectively, p = 0.032).Qualitative themes included: "Sharing resources," "spending money," "few changes," for those without children at home; "working at home can be isolating," including the subtheme, "balancing act": "working in isolation," "working more," for those with children at home.

DISCUSSION

Amongst women in academia, including both students and faculty, those with children at home have disproportionately worse mental health than those without children at home.

Relationship between sociodemographics, healthcare providers' competence and healthcare access among two-spirit, gay, bisexual, queer and other men who have sex with men in Manitoba: results from a community-based cross-sectional study

OBJECTIVE

Little is known about barriers to healthcare access for two-spirit, gay, bisexual and queer (2SGBQ+) men in Manitoba.

DESIGN

Data were drawn from a community-based, cross-sectional survey designed to examine health and healthcare access among 2SGBQ+ men.

SETTING

Community-based cross-sectional study in Manitoba, Canada.

PARTICIPANTS

Community-based sample of 368 2SGBQ+ men.

OUTCOMES

Logistic regression analyses assessed the relationship between sociodemographics, healthcare discrimination, perceived healthcare providers' 2SGBQ+ competence/knowledge and two indicators of healthcare access (analytic outcome variables): (1) having a regular healthcare provider and (2) having had a healthcare visit in the past 12 months.

RESULTS

In multivariate analyses, living in Brandon (adjusted OR (AOR)=0.08, 95% CI 0.03 to 0.22), small cities (AOR=0.20, 95% CI 0.04 to 0.98) and smaller towns (AOR=0.26, 95% CI 0.08 o 0.81) in Manitoba (compared with living in Winnipeg), as well as having a healthcare provider with poor (AOR=0.19, 95% CI 0.04 to 0.90) or very poor competence/knowledge (AOR=0.03, 95% CI 0.03 to 0.25) of 2SGBQ+ men's issues (compared with very good competence) was associated with lower odds of having a regular healthcare provider. Living in Brandon (AOR=0.05, 95% CI 0.02 to 0.17) and smaller towns (AOR=0.25, 95% CI 0.67 to 0.90) in Manitoba (compared with living in Winnipeg) was associated with lower odds of having a healthcare visit in the past 12 months, while identifying as a gay man compared with bisexual (AOR=12.57, 95% CI 1.88 to 83.97) was associated with higher odds of having a healthcare visit in the past 12 months.

CONCLUSIONS

These findings underscore the importance of reducing the gap between the healthcare access of rural and urban 2SGBQ+ men, improving healthcare providers' cultural competence and addressing their lack of knowledge of 2SGBQ+ men's issues.

Sekuwe (My House): building health equity through Dene First Nations housing designs

The Truth and Reconciliation Commission of Canada determined that the Dene people, among other Indigenous groups, experienced cultural genocide through policies that separated them from their lands and resources, and from their families, languages, cultures, and by forcibly sending children to Indian Residential Schools. The resultant social inequity is manifested in conditions of social injustice including inadequate housing. The Dene healthy housing research was a continuing partnership between the two Dene First Nation communities, the university and a provincial First Nation non-government organisation. This project engaged the creative energies of university students and Dene senior-high students to create and articulate Dene healthy housing so that concepts/plans/designs are ready for future funding interventions. We co-developed methods and networks to reframe housing as a social determinant of health and an important factor in social justice. This project reflects the fundamental requirement for a respectful understanding of Dene perspectives on housing and health and the need for Dene control over their built environment.

A Dene First Nation's community readiness assessment to take action against HIV/AIDS: a pilot project

Background: Among Indigenous people in Canada the incidence of HIV is 3.5 times higher than other ethnicities. In Manitoba First Nations, Metis and Inuit people are disproportionately represented (40%) among people who are new to HIV care. Northlands Denesuline First Nation (NDFN) identified the need to revisit their level of knowledge and preparedness for responding to the increasing rates of HIV. NDFN piloted a community readiness assessment (CRA) tool to assess its appropriateness for use in northern Manitoba.

Methods: A First Nation and non-First Nation research team trained to administer the CRA tool at NDFN in Manitoba. Five informants were interviewed using the CRA tool and the responses were scored, analysed and reviewed at community workshops and with stakeholders to develop a 1-year action plan.

Results: CRA training was best conducted in the community. Using the readiness score of 2.4 along with feedback from two workshops, community members, the research team and stakeholders, we identified priorities for adult education and youth involvement in programmes and planning.

Conclusions: In response to the increasing incidence of HIV, a northern First Nation community successfully modified and implemented a CRA tool to develop an action plan for culturally appropriate interventions and programmes.

Latent tuberculosis treatment completion rates from prescription drug administrative data

OBJECTIVE

In the province of Manitoba, Canada, given that latent tuberculosis infection (LTBI) treatment is provided at no cost to the patient, treatment completion rates should be optimal. The objective of this study was to estimate LTBI treatment completion using prescription drug administrative data and identify patient characteristics associated with completion.

METHODS

Prescription drug data (1999-2014) were used to identify individuals dispensed isoniazid (INH) or rifampin (RIF) monotherapy. Treatment completion was defined as being dispensed INH for ≥ 180 days (INH180) or ≥ 270 days (INH270) or RIF for ≥ 120 days (RIF120). Logistic regression models tested socio-demographic and comorbidity characteristics associated with treatment completion.

RESULTS

The study cohort comprised 4985 (90.4%) persons dispensed INH and 529 (9.6%) RIF. Overall treatment completion was 60.2% and improved from 43.1% in 1999-2003 to 67.3% in 2009-2014. INH180 showed the highest completion (63.8%) versus INH270 (40.4%) and RIF120 (27.0%). INH180 completion was higher among those aged 0-18 years (68.5%) compared with those aged 19+ (61.0%). Sex, geography, First Nations status, income quintile, and comorbidities were not associated with completion.

CONCLUSIONS

Benchmark 80% treatment completion rates were not achieved in Manitoba. Factors associated with non-completion were older age, INH270, and RIF120. Access to shorter LTBI treatments, such as rifapentine/INH, may improve treatment completion.

Human host defence peptide LL37 and anti-cyclic citrullinated peptide antibody in early inflammatory arthritis

Objective

Antibodies to citrullinated peptides (anti-CCP) develop in individuals predisposed to rheumatoid arthritis (RA). Neutrophil extracellular traps are a major source of citrullinated antigens and the immunomodulatory host defence peptide LL-37. Vitamin D regulates LL-37 expression. This study assessed the associations of LL-37 and anti-CCP, vitamin D metabolites and vitamin D receptor (VDR) polymorphisms in early inflammatory arthritis (EIA).

Methods

Serum LL-37, 25-hydroxy-vitamin D (25OHvitD) and anti-CCP were measured by ELISA in treatment naïve EIA (n = 181). VDR single nucleotide polymorphisms (Fok1, Bsm1, Apa1, Taq1, Cdx-2) and HLADRB1 shared epitope (SE) alleles were detected by DNA amplification. Associations were tested in multivariable models. Median (25%, 75%) or percentiles are reported.

Results

Participants (70 % female, age 56 [45, 66] years, disease activity score [DAS28ESR3var] 3.7 [2.8, 4.8], 41 % anti-CCP positive, 68 % RA) had low serum 25OHvitD; 20.5 nmol/L (13.9, 29.0). In multivariable models, controlling for age, sex, SE, smoking and vitamin D deficiency, LL37 level (top quartile) associated with anti-CCP seropositivity (OR 22; 95% CI 4 to 104).

Conclusions

Levels of circulating LL-37 are associated with anti-CCP seropositivity. LL37 activity may be one mechanism linking infection and toxin exposure to anti-CCP generation.

ELIXIR-UK role in bioinformatics training at the national level and across ELIXIR

ELIXIR-UK is the UK node of ELIXIR, the European infrastructure for life science data. Since its foundation in 2014, ELIXIR-UK has played a leading role in training both within the UK and in the ELIXIR Training Platform, which coordinates and delivers training across all ELIXIR members. ELIXIR-UK contributes to the Training Platform’s coordination and supports the development of training to address key skill gaps amongst UK scientists. As part of this work it acts as a conduit for nationally-important bioinformatics training resources to promote their activities to the ELIXIR community. ELIXIR-UK also leads ELIXIR’s flagship Training Portal, TeSS, which collects information about a diverse range of training and makes it easily accessible to the community. ELIXIR-UK also works with others to provide key digital skills training, partnering with the Software Sustainability Institute to provide Software Carpentry training to the ELIXIR community and to establish the Data Carpentry initiative, and taking a lead role amongst national stakeholders to deliver the StaTS project – a coordinated effort to drive engagement with training in statistics.

Vitamin D, serum 25(OH)D, LL-37 and polymorphisms in a Canadian First Nation population with endemic tuberculosis

BACKGROUND

Canadian First Nation populations have experienced endemic and epidemic tuberculosis (TB) for decades. Vitamin D-mediated induction of the host defence peptide LL-37 is known to enhance control of pathogens such as Mycobacterium tuberculosis.

OBJECTIVE

Evaluate associations between serum levels of 25-hydroxy vitamin D (25(OH)D) and LL-37, in adult Dene First Nation participants (N = 34) and assess correlations with single nucleotide polymorphisms (SNPs) in the vitamin D receptor (VDR) and vitamin D binding protein (VDBP).

DESIGN

Venous blood was collected from all participants at baseline (winter and summer) and in conjunction with taking vitamin D supplements (1,000 IU/day) (winter and summer). Samples were analysed using ELISA for concentrations of vitamin D and LL-37, and SNPs in the VDR and VDBP regions were genotyped.

RESULTS

Circulating levels of 25(OH)D were not altered by vitamin D supplementation, but LL-37 levels were significantly decreased. VDBP and VDR SNPs did not correlate with serum concentrations of 25(OH)D, but LL-37 levels significantly decreased in individuals with VDBP D432E T/G and T/T, and with VDR SNP Bsm1 T/T genotypes.

CONCLUSIONS

Our findings suggest that vitamin D supplementation may not be beneficial as an intervention to boost innate immune resistance to M. tuberculosis in the Dene population.

Dietary intake of vitamin D in a northern Canadian Dené First Nation community

BACKGROUND

Increased awareness of the wide spectrum of activity of vitamin D has focused interest on its role in the health of Canada's Aboriginal peoples, who bear a high burden of both infectious and chronic disease. Cutaneous vitamin D synthesis is limited at northern latitudes, and the transition from nutrient-dense traditional to nutrient-poor market foods has left many Canadian Aboriginal populations food insecure and nutritionally vulnerable.

OBJECTIVE

The study was undertaken to determine the level of dietary vitamin D in a northern Canadian Aboriginal (Dené) community and to determine the primary food sources of vitamin D.

DESIGN

Cross-sectional study.

METHODS

Dietary vitamin D intakes of 46 adult Dené men and women were assessed using a food frequency questionnaire and compared across age, gender, season and body mass index. The adequacy of dietary vitamin D intake was assessed using the 2007 Adequate Intake (AI) and the 2011 Recommended Dietary Allowance (RDA) values for Dietary Reference Intake (DRI).

RESULTS

Mean daily vitamin D intake was 271.4 IU in winter and 298.3 IU in summer. Forty percent and 47.8% of participants met the vitamin D 1997 AI values in winter and summer, respectively; this dropped to 11.1 and 13.0% in winter and summer using 2011 RDA values. Supplements, milk, and local fish were positively associated with adequate vitamin D intake. Milk and local fish were the major dietary sources of vitamin D.

CONCLUSIONS

Dietary intake of vitamin D in the study population was low. Only 2 food sources, fluid milk and fish, provided the majority of dietary vitamin D. Addressing low vitamin D intake in this population requires action aimed at food insecurity present in northern Aboriginal populations.

Killer immunoglobulin-like receptor (KIR) centromeric-AA haplotype is associated with ethnicity and tuberculosis disease in a Canadian First Nations cohort

Killer immunoglobulin-like receptors (KIR) on natural killer (NK) cells interact with other immune cells to monitor the immune system and combat infectious diseases, such as tuberculosis (TB). The balance of activating and inhibiting KIR interactions helps determine the NK cell response. In order to examine the enrichment or depletion of KIRs as well as to explore the association between TB status and inhibitory/stimulatory KIR haplotypes, we performed KIR genotyping on samples from 93 Canadian First Nations (Dene, Cree, and Ojibwa) individuals from Manitoba with active, latent, or no TB infection, and 75 uninfected Caucasian controls. There were significant differences in KIR genes between Caucasians and First Nations samples and also between the First Nations ethnocultural groups (Dene, Cree, and Ojibwa). When analyzing ethnicity and tuberculosis status in the study population, it appears that the KIR profile and centromeric haplotype are more predictive than the presence or absence of individual genes. Specifically, the decreased presence of haplotype B centromeric genes and increased presence of centromeric-AA haplotypes in First Nations may contribute to an inhibitory immune profile, explaining the high rates of TB in this population.

Vitamin D in a northern Canadian first nation population: dietary intake, serum concentrations and functional gene polymorphisms

The wide spectrum of vitamin D activity has focused attention on its potential role in the elevated burden of disease in a northern Canadian First Nations (Dené) cohort. Vitamin D insufficiency, and gene polymorphisms in the vitamin D receptor (VDR) and vitamin D binding protein (VDBP) have been implicated in susceptibility to infectious and chronic diseases. The objectives of this study were to determine the contribution of vitamin D from food, and measure the serum concentrations of 25-hydroxyvitamin D(3) (25-OHD(3)) and VDBP in Dené participants. Single nucleotide polymorphisms (SNPs) associated with the dysregulation of the innate immune response were typed and counted. Potential correlations between the SNPs and serum concentrations of 25-OHD(3) and VDBP were evaluated. Venous blood was collected in summer and winter over a one-year period and analyzed for 25-OHD(3) and VDBP concentrations (N = 46). A questionnaire was administered to determine the amount of dietary vitamin D consumed. Sixty-one percent and 30% of the participants had 25-OHD(3) serum concentrations <75 nmol/L in the winter and summer respectively. Mean vitamin D binding protein concentrations were within the normal range in the winter but below normal in the summer. VDBP and VDR gene polymorphisms affect the bioavailability and regulation of 25-OHD(3). The Dené had a high frequency of the VDBP D432E-G allele (71%) and the Gc1 genotype (90%), associated with high concentrations of VDBP and a high binding affinity to 25-OHD(3). The Dené had a high frequency of VDR Fok1-f allele (82%), which has been associated with a down-regulated Th1 immune response. VDBP and VDR polymorphisms, and low winter 25-OHD(3) serum concentrations may be risk factors for infectious diseases and chronic conditions related to the dysregulation of the vitamin D pathway.

Effect of vitamin D supplementation on Mycobacterium tuberculosis-induced innate immune responses in a Canadian Dené First Nations cohort

Canadian First Nations (FN) population experiences a high burden of tuberculosis. Vitamin D is known to enhance the expression of innate immune effectors, including cathelicidin LL-37, for protection against infections. In this study we performed longitudinal analyses to investigate the impact of vitamin D supplementation on macrophage responses to Mycobacterium tuberculosis (Mtb) lipoprotein (TLR2/1L), in Canadian Dené FN participants compared to Caucasian participants. Serum 25(OH)D and LL-37 levels were evaluated by ELISA. Transcriptional responses and protein expression of TLR2/1L-induced LL-37 and other innate immune cytokines were monitored in monocyte-derived macrophages (MDMs) before and after 8 months of vitamin D supplementation. In this study we showed that serum levels of LL-37 decreased after vitamin D supplementation in both Dené and Caucasian participants. There was no difference in TLR2/1L-induced LL-37 expression in MDMs in the two groups, either pre- or post-vitamin D supplementation. However, vitamin D supplementation markedly enhanced TLR2/1L-induced responses in MDMs e.g. IL-6, IL-12 and IL-23 among Caucasians but not in the Dené participants. In contrast, after vitamin D supplementation TLR2/1L-induced responses e.g. IL-1β, IL-8 and IL-12 were significantly reduced in the Dené MDMs. These results indicate that vitamin D supplementation enhanced TLR2/1L-induced innate immune macrophage responses in the Caucasian but not in the Dené participants. We hypothesize that cytokines may be differentially regulated in Canadian FN compared to Caucasians, in particular those that influence Th-1 and Th-17 responses required for the control of Mtb.

Differential cytokine genotype frequencies among Canadian Aboriginal and Caucasian populations

Genetic diversity related to the human immune response is a key factor in individual and population survival throughout human history. Population diversity in disease susceptibility and resistance have been identified and linked to differences in cytokine mRNA and protein expression levels. Polymorphisms in the regulatory regions of cytokine genes can influence gene transcription levels and they have been associated with susceptibility to, and/or severity of, autoimmune disorders such as rheumatoid arthritis, meningococcus and sepsis. It is reported here that in two study populations, Canadian Aboriginal individuals have a higher frequency of cytokine single-nucleotide polymorphisms favouring a low production of TNFalpha, IFNgamma and IL-10 and high production of IL-6 as compared to a Caucasian population. We postulate that the evolution of this unique cytokine genotype profile may be linked to the Aboriginal adaptation to selection pressures related to an environment in which helminthic, parasitic and fungal infections predominated.